Various types of electromagnetic field generators have existed for some time. For example, U.S. Pat. No. 6,933,819 describes an electromagnetic field generator that is capable of generating multiple frequencies. This patent is specifically incorporated herein, by reference, for all that it discloses and teaches. Multi-frequency electromagnetic generators can be used for various purposes, including use as energy transfer devices. Electromagnetic field generators can also be used for testing and calibration of flux meters, including flux meters capable of detecting multiple frequencies.